why aren't you also a parent?
GSA, Huge sympathies for your loss, I too had a miscarriage, though much earlier in the pregnancy. Until one actually lives through anything like that they really have no idea how awful it can feel. I would never presume to know how much harder it's been for you to lose her so much later in your pregnancy, so you have my deepest sympathies.
My situation is still quite new as poly and yet its also very committed. I essentially have two homes now with children in both. All three of us have taken all the children into our hearts whether biologically connected or not. We see their games, plays, activities.... to us they are all our children, we share in their joys and hardships.
By reading your signature line; you all live together? Why is Samantha not sharing everything with you like a spouse? Why aren't you being considered a parent to the child?
Of course everyone's poly life is different and everyone finds there own way and everyone's way is unique to them. If it's at all possible, I would wish for you that even if you don't wind up having any children biologically of your own (and you fortunately have a lot of years for that option) that the children whom you already love in your heart will know you as one more special person in their life to love them and that that may help you heal.
So, so sorry for your pain, hopefully sharing helps a tiny bit and that many of us are now sending you love. Barring a 'magic pill' for the pain, I hope that you feel loved and supported.